Glass bead product

ABSTRACT

An apparatus for making beads and a bead product are provided in the form of a member rotatable about a generally vertical axis having an outer peripheral edge adapted to discharge molten material in the form of pellets as the member rotates, means for creating heat on said member sufficient to maintain a molten layer of material being discharged on the walls of said member and fluid cooling means receiving discharged pellets which may be glassy generally spherical particles as solids or having frothy uniform voids surrounded by a glassy smooth surface or having integral crystalline elements.

This application is a division of my copending application, Ser. No.515,191, filed Oct. 16, 1974, now abandoned which was acontinuation-in-part of my copending application Ser. No. 291,262, filedSept. 22, 1972 U.S. Pat. No. 3,856,899 which was in turn acontinuation-in-part of Ser. No. 35,962, filed May 11, 1970 U.S. Pat.No. 3,694,528.

This invention relates to apparatus for making solid or cellular beadsand to a bead product and particularly to apparatus for making beadsfrom materials such as glass, slag, alumina, and other high meltingpoint materials, earths, metals and the like and to the resulting beadproduct.

There is a very substantial demand for solid and high strength beads,both solid and cellular, of a great variety of materials such as glass,slag, metal and the like. These beads are used for a great variety ofpurposes, e.g., as proppants in oil well drilling, as reflectors inreflective paints, etc. There is particularly a need for an apparatusfor converting metallurgical slag to high strength low porosity pelletssuitable for substitution for glass pellets. There is in addition arecently developed need for simulated lunar materials to be used ascomparison samples in the study of lunar soil samples.

I have discovered an apparatus which provides unique control over thebead formation and permits beads to be made of almost any normally solidmaterial in its molten state. I have found, for example, that bymaintaining a reducing condition at the apparatus, I can make blastfurnace slag beads which have a crystalline structure. With the samematerial, I can produce a transparent amorphous pellet under neutral andmildly oxidizing conditions or with a highly oxidizing condition, I canproduce a black, shiny, glass-like opaque bead. Thus, I have a very highdegree of control over the product which is produced by the apparatus ofmy invention.

Preferably I feed molten material to be pelletized or formed into beadsaxially downwardly through a rotating refractory tube through acontrolled atmosphere and discharge the same horizontally from therotating circular edge or alternatively I rotate a solid consumablemember to be pelletized while melting and maintaining a constant flow ofpellets from the end thereof. The rotating tube may be of refractorymaterial or it may be formed of a non-refractory shell having an innerrefractory lining. By refractory I mean any material (ceramic or metal)capable of withstanding the destructive effect of the temperature andmaterial being handled. Preferably the beads or pellets are dischargedhorizontally across a fluid coolant so that they contact the surface ofthe coolant in a rolling action effecting rapid submergence whichreduces the temperature rapidly without undue shock and permits thematerial to reach equilibrium. The refractory tube is preferably formedof carbon terminating in a generally frusto conical shape with themolten material being fed in at the smaller end and discharged from theperiphery of the larger bottom end. The tube is rotated and the bottomcircular edge acts as the discharge edge or a stationary tube maydischarge centrally onto a rotating disc at its bottom, which discprovides the rotating circular discharge edge. Similar, where a solidconsumable member is used, and by solid I include a member having ahollow axis, the member is rotated while being lowered axially into ortoward a heat source and a conical depression formed from melting anddischarging pellets from the edge, essentially as in the case of thecarbon tube. The controlled atmosphere may be reducing, neutral oroxidizing and may be created, at least in part by a carbon arc withinthe tube or by a gas burner within the tube. Preferably the heat sourceis in the form of two opposing heating members which may be opposingelectrodes or opposing gas burners between which the molten material isheated.

Oxidizing atmosphere may be created in conjunction with the carbon arcby permitting air to flow upward over the surface of the molten materialwhile the carbon arc operates centrally within the tube. Air is highlyheated as it passes between the arc and the surface of the moltenmaterial. The valve at the top of the tube controls this flow of air.

In the foregoing general description of my invention, I have set outcertain objects, purposes and advantages of this invention. Otherobjects, purposes and advantages of this invention will be apparent froma consideration of the following description and the accompanyingdrawings in which:

FIG. 1 is a side elevation, partly in section of an apparatus accordingto this invention;

FIG. 2 is a side elevational view of a second embodiment of an apparatusaccording to my invention;

FIG. 3 is a side elevational view partly in section of a thirdembodiment of an apparatus according to this invention;

FIG. 4 is a side elevational view, partly in section of a solidconsumable member according to my invention;

FIG. 5 is a side elevational view of the member of FIG. 4 duringpelletizing;

FIG. 6 is a section through still another embodiment of means forpracticing this invention; and

FIG. 7 is a section through another embodiment of apparatus forpracticing this invention.

Referring to the drawings and particularly to FIGS. 1-3, I haveillustrated a graphite tube 10 mounted in an annular support ring 11rotatable on spaced supports 12. The tube 10 is enlarged at its lowerend into a frusto conical member 13 having a machined annular dischargelip 14. A concave reflector 15 is shown beneath the frusto conicalmember 13 with its edge parallel to and spaced from the outer edge ofthe frusto conical member 13. The heat reflector may be any othersuitable shape e.g. convex, or frusto conical, or pointed, as desiredbecause the heat reflector does not engage the molten material. Acentral electrode 16 allowing vertical movement and lateral electrodes17 are provided in the reflector 15 extending upwardly into the cone 13.These electrodes are connected to a source of electrical current (notshown) for causing an arc to move from one to another of said electrodeswhereby a high temperature may be created within the area beneath thecone 13. Inlet nozzles 18 are provided in the reflector 15 to permit airor other gas to be introduced into the area beneath the cone 13 wherebythe nature of the atmosphere surrounding the molten material within thecone can be controlled. The molten material to be pelletized or beadedis introduced through inlet pipe 19 into a feeder 20 which dischargesinto the top of tube 10. Molten material is introduced into feeder 20and distributed along the inner wall of the tube 10. The first suchmaterial will solidify to form a thin protective lining 21 along theinner wall of the tube 10 and cone 13 after which the molten material 22will flow downwardly along the inner wall of tube 10 and cone 13 and bedischarged as pellets 23 or beads from the rotating periphery ofdischarge lip 14. The thickness of the protective lining 21 may becontrolled by heating or cooling tube 10 with an air blast or a blast ofhot gases or by changing the rate of feed. The ring 11 is driven by amotor 24 through a gear train 24a.

A carbon electrode 25 may extend downwardly in tube 10 to be used withor alternatively to electrodes 17.

The foregoing arrangements permit great latitude in the control offluidity of the molten material in tube 10. It provides the followingpossibilities:

(a) Arc heating wherein the arc moves between electrodes 16 and 25 andin which the position of the arc may be adjusted by vertical movementand lateral movement of the electrodes 16 and 25;

(b) Resistance heating wherein the lateral electrodes 17 are of oppositepolarity and the circuit is completed through the molten material 22.

(c) A combination of arc and resistance heating using the severalelectrodes at the same time.

The size of the beads or pellets produced by the foregoing apparatus canbe adjusted by the rate of feed of molten material into the tube, by thespeed of rotation of the tube, by the degree of flair or slope at thefrusto conical end of the tube, by the temperature at the discharge endof the tube or by any combination thereof. Cellular beads possessingvery uniform bubbles have been produced from slags and glass when themolten material is subjected to the high temperature carbon vapor zoneof the arc provided the carbon vapor zone is located close to thedischarge edge of the apparatus. This creates a reducing condition. Themolten material foams, but is discharged immediately (in pellet form)from a near horizontal plane.

Cellular beads of this type may be discharged on a cool flat solidsurface such as concrete, metal or in air.

The apparatus illustrated in FIG. 2 is essentially the same as that ofFIG. 1 except that instead of the electrodes for heating, I provide agenerally conical gas burner 30 centrally of reflector 31. All otherparts are identical and bear like numbers with the addition of a primesign.

The apparatus illustrated in FIG. 3 provides a hollow graphite feed tube40 extending vertically above a rotating disc 41. A heat reflector hood42 surrounds the feed tube 40 and extends to a point adjacent theperiphery of disc 41. Electrodes 43 extending downwardly through thehood may be adjusted so as to contact molten material on disc 41 andheat by resistance or they may be used to arc above the material to forman arc heating system or a combination of the two. Molten material 44 tobe pelletized or beaded is fed into the upper end of tube 40 and flowsdown onto the axis of rotating disc 41 where it moves radially outwardlyto the edge forming a film over the disc and is discharged as beads. Theelectrodes 43 are used to heat the molten material to increase itsfluidity or to add carbon or to otherwise modify it as has already beendiscussed in connection with FIG. 1.

In FIG. 6 I have illustrated the inverted equivalent of the apparatus ofFIG. 1. In this form a crucible 70 on shaft 71 driven by motor 72 isrotated about a vertical axis to discharge pellets 73 from lip 74 ofinterior conical surface 75. Molten or solid material 76 is fed fromreservoir 77. Heat is provided by gas flames 78. A gaseous atmospheremay be provided by tube 79.

The feed tube may be a consumable tube 60 which itself supplies thematerial for pelletizing as shown in FIGS. 4 and 5. For example scrappipe may form the tube and be melted at its lower end while beingrotated at high speed thus causing beads to be discharged.

Before starting the rotation and melting the consumable tube could havean end 61 as shown in FIG. 4. After the process has been operating theconsumable tube develops a cone shaped depression 62 as shown in FIG. 5.The cone shaped depression may be altered by changing the heat source 63size and intensity with respect to the diameter of the element. It isdesired to maintain the cone shape depression because in so doing, thedischarge rim is easier to maintain and the cone depression tends toconcentrate the applied heat and restrain both the heat and flowingmaterial for most efficient operation. The greatest heat is applied tothe center of the cross section and maintains the cone shaped depressionas the tube (element) rotates.

The consumable element may be made of a great variety of materials andin different ways. The consumable element may be made up of compactedparticles of glass, slag, earths, metals, plastics and minerals; it maybe made of wrought elements such as rolled, forged or extruded metals,glass, earths, metals, plastics and minerals; it may be a cast elementof any material; or it may be a fabricated element of any finely dividedmaterial in a pipe, a wire mesh tube or any other restraining meanscapable of restraining the materials during rotation. A suitable bindermay be used or metal chips or turnings incorporated into the mixture andcompacted to aid in holding the element together. Under neutral orreducing conditions any added metal used as a restraining means willseparate from non-metals at the discharge rim during pelletization.

In the case of operating a conical feed source, the rate of feed andamount of heating may in all cases be regulated by the shape of thetube. For example the tube may be enlarged intermediate its ends so asto retard downward movement. With such an apparatus "fly ash" can bemelted and pelletized in the tube without prior melting.

In FIG. 7 I have shown a pair of opposing gas burners 80 and 81 in avertical axis arrangement with a rotating pelletizer 82. The upperburner 80 is surrounded with a housing 83 through which finely dividedparticles 84 of feed stock such as slag, glass cullet or the like arefed onto the circular flame zone 85 where they are heated and melted anddischarged as beads as herein described. The opposing burners may feedopposing streams of fuel for heating the particles or a mixture of fueland air or one may feed fuel and the other air or oxygen or anycombination thereof. The fuel may be any combustible gas, oil orpowdered coal. This opposing burner arrangement produces a very hot andefficient flame that burns in a lateral direction in a continuous circlewhich is superior to the orifice type burner used in other forms of thisinvention.

The form of the flame circle produced by the opposing burners 80 and 81may be varied by varying the distance between burners, by changing therelative pressures in the opposing burners so that the flame can have atop surface which is convex, concave, or substantially flat.

The apparatus of my application can perhaps be best understood bydescribing it in connection with the treatment of blast furnace slag topelletize the same.

Molten slag is caused to flow through the spinning tube which possessesgreat conductive ability for the inherent heat of the process.

The initial flow of molten material enters the top end of the tube, butdue to the tube's heat conductivity, the material begins a progressivesolidification against the inside wall (I.D.) which forms a lining fromtop to bottom of the tube. Because of the rapid solidification andrelease of gases during solidification the lining forms a porousinsulating barrier between the tube wall and the molten material thatcontinues to flow. It is to be understood that the lining is solidagainst the tube wall and possesses a temperature gradient whichincreases in the direction away from the tube wall so that the liningnearest the central axis of the tube is at approximately the sametemperature as that of the feed molten material.

The thickness of the lining may be controlled by extracting more or lessheat through the tube walls via air or water spray cooling as well asrate of feed.

I have found that for a spinning graphite tube having a 1/2 inch thickwall the boundary air on the outside surface is sufficient to maintain a1/8 inch thick lining over the I.D. even though a carbon arc wasmaintained within 1/2 inch of the lining. The arc was maintained with5/16 inch electrodes at 75 amps + 30 volts.

After the above mentioned lining is formed molten slag continues to flowthrough the tube in a downward direction until it reaches the dischargeend.

In this process, a continuous flowing film of molten material is formedfrom the point of feed-in at the top of the tube to the discharge pointat the bottom of the tube. The discharge point is the point at which thefilm reaches its maximum diameter and contact with its restraint iseliminated.

The restraint may be a flat disc (FIG. 3) over which the molten materialis urged to flow as a film in contact with the entire disc surface orthe restraint may be a short truncated cone section (FIGS. 1 and 2) withconcavity sloping upward or downward or the restraint may be asaucer-shaped disc. The shape of the restraint may be selected accordingto the length of time the molten material is to be subjected to anydesired set of conditions.

A straight cylindrical tube offers the shortest film spread because inthis case the molten material will be in partial restraint over only thedistance of the wall thickness from supply to pelletizing or rupturepoint.

ACTION AT DISCHARGE POINT

I have found that transparent pellets may be produced from furnace slagmerely by causing molten slag to react with the boundary air thatattends a spinning shape.

The reaction between molten blast furnace slag and air is exothermic andcontinues to completion as the slag remains molten and has an adequatesupply of air contacting the surface. The various elements in blastfurnace slag (and other furnace slags as well) which are capable ofbeing oxidized such as carbon, sulfur, carbon monoxide, etc. will reactwith air to produce heat and aid pelletization and I have taken fulladvantage of this phenomenon in my process.

In my work I have found that blast furnace slag that possesses theelements normally inherent in the slag at the time of discharge from thefurnace may be (while still molten) spun through air with the resultthat the slag changes from a limey crystalline appearance progressivelyto a transparent amorphous appearance. The lead side of the slag becomesclear first and this will continue as long as the slag remains moltenand air is present until the entire mass becomes transparent.

In my process I control the rate and duration of this exothermicreaction and dictate the time prior to pelletization that the reactionwill take place.

I produce crystalline pellets from furnace slags by processing the slagin an air excluded atmosphere. In other words, I process the slag in itsown gases while maintaining a molten state just sufficient to causepellets to form at the discharge end of the apparatus. At the dischargepoint or zone I maintain an ambient atmosphere of a reducing natureagain, excluding air so that the forming pellets do not react to becometransparent and noncrystalline.

I have found that blast furnace slags for example is highly absorbantrelative to carbon from carbon bearing gases at temperatures as low as1600° F. This absorption can be made to take place in a carbonaceousatmosphere without causing bubbles to form within the slag.

CRYSTALLIZATION OF GLASSY COMPOSITIONS

When glassy compositions such as may be derived from blast furnace slag,for example, are reheated, the glassy material becomes opaque because ofthe growth of crystals within the glassy material.

Definite visible evidence of the crystallization is obtained at about1600° F. The degree of crystallization increases as the reheattemperature increases and time is prolonged and as the cooling time isprolonged.

In my work, using glassy spherules of typical blast furnace slagcompositions, I have found that the crystal growth starts at the surfaceof the spherule and progresses inwardly as heating continues. Eventuallythe entire spherule is recrystallized. The process will follow theteachings of a phase diagram for the selected composition.

It has been found that as the crystals grow inwardly pressure is builtup within the spherule and at reheat temperatures of about 1900° to2200° F. the pressure becomes great enough to cause rupture to takeplace followed by the ejection of a liquid (liquid phase of thecomposition) through the cracks in the spherule surface.

When heating is continued the ejected liquid will crystallize withejection of more liquids from the original ejecta.

The applicant provides this product and the process as a means or a toolto explain why large size glassy shapes are rarely found in Lunar Soilsamples and it explains the shock metamorphism theory. It is suggestedby the applicant that the rupture through the crystalline structure maycause characteristics to develop that are identical to those produced byimpact.

I have transformed transparent amorphous slag into crystalline opaqueslag merely by heating the transparent slag in a carbonaceous (reducing)atmosphere. The reaction was evident at temperatures as low as 1600° F.

In my process I produce crystalline pellets merely by processing themolten slag in its own gases and maintaining a carbonaceous atmospherethrough the pelletizing stage of operation. This carbonaceous atmosphereis blown through the opening between the heat reflector and the ends ofthe tube (or if a flat disc is used between the heat reflector and theedge of the rotating disc). The atmosphere envelopes the pellets as theyfly to the coolant and solidify. Note, in the production of transparentnon-crystalline pellets the carbonaceous atmosphere is omitted and anatmosphere equivalent to air is substituted within the lower end of thetube and is blown out in the same manner so as to form an oxidizing orneutral envelope.

DISRUPTION OR PELLETIZING WITH FLOWING PRESSURIZED GAS AT HIGHTEMPERATURES.

During normal operation of this invention using a closed end rotatingvessel with the heat reflector in position and while injecting gas orair through the ports in the heat reflector the hot gases blow throughthe opening between the rotating vessel and the heat reflector.

During such normal operation it has been found that if the volume of gasflowing through the opening is small, the velocity of the gas throughthe opening is correspondingly low and will not exceed the velocity ofthe molten material also flowing through the opening.

When the operation is conducted at high rotational speed and theatmosphere blown through the opening must be extended to cover thebroader trajectory pattern of the pellets, the volume of gas or airinjected into the rotating vessel is increased. This causes the velocityof hot gases through the opening to increase and surpass the velocity ofthe molten material also flowing through the opening. As a result, thehigh velocity gases produce a secondary pelletizing action in additionto the primary pelletization caused by the rotational forces alone.

A greater or more powerful disruption of the molten material results andfiner or smaller sized products result. It has been found that spherulesand crystals are thus produced at rates even greater than during normaloperation where the gas velocity is less than or equal to the velocityof the discharging molten material.

I accordingly provide an apparatus for pelletizing and disintegrating afilm of molten material into spherules and crystals through the actionof a high velocity stream of hot gas or air upon a film of moltenmaterial wherein both the gases and the molten material are forcedthrough the same opening and flow in the same direction.

Pelletizing methods of the prior art normally require that metal beexcluded from the slag prior to pelletizing to avoid explosions.

In my process, separation of molten metal from the molten slag is notrequired. In fact, I have pelletized metal and slag simultaneously withno fear of explosions.

Separation of slag and metal may be made in the process and two usefulspherical products result. Each will offset the cost of producing theother. This is unique to my invention.

In fact, I provide an apparatus for producing both metal shot andmineral pellets in one operation wherein waste materials such as metalchips and grinding dust are introduced into the tube or into the moltenslag as it enters the apparatus (or prior to entry) and the combinationis processed into pellets of a useful nature.

It is well known that slags discharged from furnaces are well in excess,temperature wise, of their melting points or solidification points. Ifmetal chips or grinding dust is added to the slag much of the excesstemperature may be utilized to melt the metal. I have produced lead,copper, steel and nickel pellets simultaneous with slag and glasspellets in this method.

In regard to grinding dust resulting from grinding various grades ofsteel it is known that the grinding dust from stainless steelconditioning contains nickel, chromium, iron and other various valuableelements. Under the reducing conditions capable in this pelletizingmethod these elements can be recovered in the form of pellets.

Also, grinding dust contains approximately 10 to 15 percent Al₂ O₃ whichadheres tightly to the metal. This Al₂ O₃ may be recovered and added tothe slag composition thereby enhancing the properties of the slag.

Heavy additions of waste metal to liquid slag may be made and pellets ofmetal and slag produced or metal and slag solids or metal and glasssolids may be used to produce beads because the process provides meansto heat the molten materials or solids being processed.

DELIVERY OF PELLETS TO COOLANT SURFACE

Pellets are discharged from the film of molten material in a singleplane and each pellet fans out giving an ever increasing spaceseparating each pellet.

Since the pellets discharge in a single plane, I locate the discharge asclose to the surface of the coolant as possible (as close as 1/16 inchto the coolant surface) and thereby deliver the pellets onto the coolantsurface with an angle of incidence so small that upon striking thecoolant surface the pellet immediately begins to rotate with a minimumof impact and the entire pellet surface is cooled rapidly and uniformlyresulting in spherical shapes as little as 0.001 inch out of round asdetermined on pellets measuring 0.030 inch to 0.200 inch diameter (notthe limit of sizes).

Pellets of glass may be similarly produced by this method wherein themolten glass flows to the discharge end of the film and is heated wellabove the last equilibrium temperature just prior to the pelletizingoperation.

The glass is heated using either carbon arc or gaseous heat to a pointwhere the molecular cohesion becomes so small because of the hightemperature and formation of relatively large gas bubbles within theglass thereby reducing the total glass cross section in the glass filmthat the glass film ruptures into discrete pellets under the influenceof centrifugal force. The pellets are discharged onto the surface ofvery hot (180° F.) to boiling water where upon the gas bubbles withinthe pellets are observed to shrink and the glass itself begins to shrinkthroughout the pellet's mass and eventually the pellet shrinks to asubstantially solid form. Because the glass and gases within aresuperheated to the same degree the pellet shrinks to a compact form fromthe center of the mass rather than from the surface inward as in priorarts.

I have found that a neutral to oxidizing temperature condition wherebythe glass is heated to above 2800° F. and higher and the glass developsa light amber tinge will produce pellets of useful purpose.

Where a cellular product is desired the arc is adjusted, close to thedischarge point and so that glass is in the vaporized carbon gas area.

I have found that by proper control of conditions as will be hereafterdescribed in more detail I can produce spherules and crystals thatposses characteristics identical with those brought back from the moon'ssurface.

Since the time when Lunar Soil was first brought to Earth a veryintensive study by many scientists has been in progress for the purposeof finding the answer to many questions regarding the chemicalcomposition, the physical properties, the magnetic properties andnumerous other unusual properties of Lunar Soil and its individualcomponents. In addition, much effort has been expended trying todetermine the mechanisms that produced the spherules, crystals andmiscellaneous particles found in the Lunar Soil. Much of the workperformed, results of investigations and the conclusions are presentedin the "Proceedings of the Apollo 11 Lunar Science Conference",published in three (3) volumes. Volume 1, Mineralogy and Petrology is ofparticular interest because it presents the findings of many scientistsand deals with Lunar Soil particles in great detail with very greatimportance being given to the spherules and crystals in the Lunar Soil.Unfortunately, work had to be conducted on the samples brought from themoon in their natural moon condition. It is known that the size of thespherules and crystals under study range from approximately 3.0millimeter down to a fraction of a micron (0.001 mm) with the averagesize of the fines being less than about 0.5 millimeters.

Many theories have been advanced as to the mechanism by which these moonspherules and crystals were formed. I have found an apparatus andproduct which duplicate the moon spherules and crystals. I havereproduced the same characteristics formed on moon spherules andcrystals under known and controlled conditions. Of great importance isthe fact that I have been able to make these products in both macro andmicro sizes. The macro size particles enables scientists to study largescale characteristics in sizes up to approximately 1/4 inch with greaterdetail than is available with the micro size spherules brought from themoon surface.

The following useful and novel products are produced by my process usingmineral compositions with or without contained metal:

1. Transparent glassy spheres.

1.1 Colorless, green, very pale yellow spheres are produced underneutral to reducing conditions at temperatures above the point where thesolid phase (crystals) are completely dissolved in the liquid phase.

1.2 Amber, brown and dark brown spheres are produced under oxidizingconditions at temperatures above the point where the solid phase(crystals) are completely dissolved in the liquid phase.

2. Transparent glass spheres exhibiting well defined crystals.

2.1 Colorless, green, very pale yellow spheres with well definedcrystals in the transparent matrix are produced under reducingconditions at lower temperatures than are used to produce spheresdescribed in 1 above. The temperature range required may be described asthat in the middle of the full temperature range spanning the phasediagram for the composition being processed. For blast furnace slagsthis appears to be approximately 2400° F. to about 2700° F.

2.2 Amber, brown and very dark brown (opaque in larger sizes) sphereswith well defined crystals in the transparent matrix are produced at thelower temperatures as described under 2.1 above, but under oxidizingconditions.

3. Transparent glassy spheres containing gas bubbles.

3.1 Glassy transparent spheres containing one or a number of randomlyscattered voids are produced under reducing neutral and/or oxidizingconditions when molten material containing residual crystals or solidphase in limited quantity is subjected to a slight increase intemperature sufficient to dissolve the crystal followed by a rate ofcooling sufficiently rapid to lower the fluidity of the matrix. It hasbeen determined and observed that the solution of crystals in the liquidphase is accompanied by the evolution of a gas. In other words, it hasbeen observed that under the conditions described above, the isolatedcrystals will be replaced by isolated gas bubbles. This is accomplishedby adjustment of heat source in this invention to increase temperatures(slightly) of the molten material just prior to being pelletized.

4. Glassy Brown Colored Spheres With Surface Crystals.

Glassy brown colored spheres that have white crystals (under reflectedlight) on the surface, partially imbedded crystals in the surface andcrystals lying just under the surface covered by a thin glassy layer arenormally produced under oxidizing conditions by this invention. Thisresult is readily observed under magnification of 60X to 100X. Thecrystals vary in shape and size and may appear quartz like or frostywhite under reflected light.

The crystals may be described relative to their attachment and locationas follows:

4.1 Crystals loosely attached to the sphere surface as by staticattraction and which can be readily brushed away from the surface.

4.2 Crystals that are firmly attached to the surface by being partiallyimbedded in the glassy matrix of the sphere.

4.3 Crystals that are completely submerged in the glassy matrix, some ofwhich are covered by only a very thin layer of glassy material.

The crystals described in 4.3 above may be residual crystals existing inthe molten material being processed or they may be the results ofrecrystallizations that occur during the air cooling of the formedspheres.

The crystals described in 4.2 may be residual crystals or products ofrecrystallization that becomes trapped in the matrix and in the spheresurface during cooling of the sphere.

The crystals described in 4.1 may be residual crystals that are set freeat the moment the molten material is disintegrated at the discharge edgeof the pelletizing apparatus or they may be crystals that areprecipitated from the matrix as they recrystallize during air cooling ofthe spheres.

The condition described under 4 above is not observed for spheresproduced under reducing conditions and high temperature conditions thatyield the colorless spheres and pastel colors of green, yellow and lightamber spheres.

The condition described in 4 above is normal for spheres produced underoxidizing conditions and particularly when the iron oxide content of thematerial is highly oxidized and lies in the approximate range of about 5to 20 percent.

One of the features inherent in my apparatus for pelletizing is thecompression of molten material while under restraint within the tube andcone shaped vessel at any temperature followed by the disintegration ofthe molten material as it leaves the restraint at the discharge edge ofthe vessel. The molten material is literally torn apart or disintegratedby tension that is developed in the molten material as the materialexpands radially around the discharge edge.

Under the fluid condition of the molten material that is induced by ahighly oxidized iron oxide content the solid phase (crystals) willactually separate from the liquid phase resulting in two distinctproducts, namely; crystals and spheres.

It is indicated by the appearance of the crystals protruding from theoxidized spheres and by the free crystals simultaneously produced thatthe oxidized liquid does not wet the crystals and it is furtherindicated that the crystals are in a state of growth rather than one ofdissolving.

5. Glassy Brown Colored Spheres With Metal "Blebs".

"Blebs" are metal attachments or partially submerged metal on or in thesurface of a sphere.

The production of spheres exhibiting metal blebs appears to be limitedto processing under oxidizing conditions.

The brown colored glassy spheres described under 4 above may alsocontain metal attachments on the surface or they may contain partiallysubmerged metal "islands" that show on the surface.

I have found the metal blebs to be solely associated with the productionof pellets (spheres) by this method and invention from a melt of mineral(such as Blast Furnace Slag) that contains, in addition to metal oxides,metallic metal such as iron, nickel or copper.

Where metal exists in the molten material (entrapped or intentionallyadded) both the metal and the mineral arrive at the discharge rim wheresome of the metal is pelletized as individual metal spheres and some ofthe metal either clings to the mineral sphere by an oxide metal bond oris encased in the mineral sphere.

Under reducing conditions metal will separate from mineral becauseneither have a great affinity for the other.

Under oxidizing conditions the metal will oxidize and this metal oxidewill have a great affinity for the oxides in the mineral liquid,consequently, the spheres in close proximity to the metal at the time offormation will exhibit the metal bleb.

If metal is encased by the mineral in spherical forms the sphere willgenerally exhibit a large void internally. The metal may be observedprotruding through the surface of the sphere or it may be observedinside the cavity in cases where the thin wall of the cavity is brokenopen.

Metal blebs may appear as roughly spherical shapes attached to thesphere surface by pin point contact or they may appear as lens-likeshapes lying on the surface of the mineral sphere or they may appear asprotruding islands of metal in the mineral surface.

Generally the point of attachment exhibits an indication that the metaloxide film (surrounding the metal) blends into the surface of themineral sphere.

The temperature of the metal and the mineral sphere appears to controlthe shape of the bleb. Temperature just above the melting point of themetal appears to yield the more spherical shaped metal attachments whilehigher temperatures appear to yield the lens-like shapes.

6. Glassy spheres Exhibiting surface craters.

These spheres are pronounced in the brown and dark brown colors and areindicative of oxidizing conditions.

The following types of craters have been observed on the applicant'sproduct:

6.1 Craters with smooth rounded edges indicative of gas release throughthe sphere surface with enough residual heat remaining in the sphere toround off the blow hole edges (rim of hole) through surface energy(surface tension).

6.2 Spheres with craters having sharp well defined rims that mayprotrude.

The sharp protruding rim is indicative of a gas break through as abubble. In this case the thin wall of the bubble at the surface of thesphere may break leaving a sharp rim at the sphere surface. Thetemperature of the sphere was insufficient to cause rounding of the rimafter the bubble broke through the surface.

6.3 Craters in spheres that contain crystals or white linings. The whiteparticles appear to be recrystallized formations extruded from thesurrounding matrix and are in great contrast because of the white colorin a dark brown background.

6.4 Glassy spheres with craters surrounded by spalled sphere surface.These are indicative of gas bubbles formed just below the surface of thesphere and which possess sufficient pressure to rupture the coveringsurface after the sphere surface has contracted and becomes "set" orrigid.

7. Cellular Spheres Containing Uniform size Gas Bubbles.

Glassy cellular spheres with a glassy smooth surface surrounding afrothy interior of uniformly sized voids. The original applicationdescribes the production of these spheres by positioning carbonelectrodes at the discharge area of the pelletizing vessel. It has beendetermined that such cellular spheres are produced from glasses andslags because of the following reactions that take place uponapplication of high heat just before the material disintegrates intopellets.

7.1 Undissolved crystals in the molten material are heated through thepoint of solution in the liquid phase and are replaced by gas bubbles.The replacement of crystals by gas bubbles has been established by theapplicant through visual observations.

7.2 Molten mineral compositions will froth when a molten composition ina reduced state is suddenly subjected to a heat source of oxidizingquality of equivalent or higher temperature. An oxidized slag or glasswill froth if suddenly heated by a heat source of reducing quality. Thisis a reversible process and may be repeated using the same unit ofmolten material.

8. Micro Sized Spheres.

During the production of cellular spheres described in 7 above it hasbeen found that micro sized spheres are produced also. These range insize from about 200 microns down to less than 1 micron.

It has been determined that these micro size spheres (duplications ofspheres found in Lunar Soil Samples) are produced when mineralcompositions such as blast furnace slags are subjected to high intensityheat sources as electric arc or oxygen-gas flames. The molten materialgenerally contains entrapped gas bubbles which move and flow with themolten material as it approaches the discharge area and, in this case,the high intensity heat source. The gas bubbles expand rapidly in a thinmembrane of the slag. The bubble bursts and the membrane flies outwardlyand each small membrane section immediately spherodizes to form microsized spheres and are carried out of the hot zone by the arc stream orhigh velocity gases of the oxygen-gas flame.

When entrapped metal exists in the molten material being processed microsized spheres of metal and the metal oxide are also produced along withspheres of the predominant mineral composition.

9. Elongated Shapes or Dumb bells.

Elongated shapes such as those found in Lunar Soil Samples are producedin the practice of this invention in the following manner.

Molten slag (example blast furnace slag) is processed through therotating vessel as described in the specifications and allowed claims.

At the discharge rim or edge of the vessel a single heat source (carbonarc for example) is positioned so that the heat therefrom isconcentrated at one point on the periphery of the rim. As the vesselrotates, the molten film of slag passes under the single heat source andis heated above the pelletizing (spherodizing) temperature.

When the normal flow of slag is processed at a high temperature and at areduced rate of flow and the pelletizer is operated at high rotationalspeed small spheres will be produced.

When the temperature of the normal flow of slag is reduced to the pointwhere the slag begins to string out at the discharge rim slightelongations will appear at the discharge point. If the single highintensity heat source is placed into operation the slight elongationswill be reheated quickly and each elongation will melt away from thepoint of attachment to the film of slag at the rim and will bedischarged therefrom as an elongated shape having a length of two ormore times the diameter. As the heated point on the rim moves from underthe single heat source the attached elongations previously describedform again and remain on the rim until they are melted by passing underthe single heat source. The principle is this:

Elongations are formed under low temperature conditions, but high enoughto permit plastic flow. The mineral will tend to string out or elongateas long as it is attached at one end. This may occur by centrifugalforce or in a flow of gas at just the right "stringing" temperature. Ifthe elongated shape is suddenly heated at its point of attachment itwill separate therefrom and as it flies through the air it will cool sothat only the detached end will round-up and the detachment will retainits elongated shape. The elongated shape must be elongated prior tobeing discharged into the air otherwise flow within the unit would takeplace in more than one plane and a distorted shape would result.

While I have set out certain preferred practices and embodiments of myinvention in the foregoing specification, it will be understood thatthis invention may be otherwise practiced within the scope of thefollowing claims.

I claim:
 1. A glass generally spherical glass particle containingnon-continuous integral crystalline matrix derived elements each onebeing at least partially enclosed within said glassy particle.
 2. Agenerally spherical glass particle as claimed in claim 1 in which thecrystalline elements are substantially pure metals.
 3. A generallyspherical glass particle as claimed in claim 1 wherein the crystallineelements are totally enclosed within said glassy particle.